Final answer:
Repeaters are used to extend the coverage area of mobile devices. They work by receiving, amplifying, and retransmitting signals to bridge communication gaps. Other wireless technologies like satellite phones and Bluetooth are structured differently and do not rely on repeaters in the same manner.
Step-by-step explanation:
Repeaters are primarily used to increase the effective communications coverage area for mobile devices that might not be able to communicate with one another due to distance or obstructions. Repeaters receive and amplify the signal before retransmitting it to extend the range of communication.
Implementations such as microwave transmission, communications satellites, and other wireless technologies have facilitated the advance in telecommunications. For instance, cell phones depend on a network of towers to transmit calls over long distances, utilizing low-powered radio transmitters that require a clear line of site to operate effectively, something that high frequency microwaves are well-suited for.
Repeaters are less typically used for satellite phones, Bluetooth devices, or wireless routers, as these technologies either already have long-range capabilities, are designed for short-range communication or operate within a fixed network infrastructure without the need for extended coverage through repeaters.